Question: $ { \left[\begin{array}{rr}{3} & {2} \\ {3} & {1}\end{array}\right]+\left[\begin{array}{rr}{3} & {1} \\ {-1} & {-2}\end{array}\right] = {?} } $
Solution: To find the sum of two matrices, add the corresponding items between each matrix. ${\left[\begin{array}{rr}{3}+{3} & {2}+{1} \\ {3}+{-1} & {1}+{-2}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rr}{6} & {3} \\ {2} & {-1}\end{array}\right]}$